A gas turbine includes a compressor that compresses air, a combustor that generates a combustion gas by burning a fuel in the air compressed by the compressor, and a turbine driven using the combustion gas. Some combustors have a pilot burner for diffusion combustion of the fuel and a main burner for premixed combustion of the fuel. With such a combustor, it is necessary to manage a ratio of the flow volumes of the fuels supplied to the respective burners.
For example, according to the technology disclosed in Japanese Unexamined Patent Application Publication No. 2012-077662 A, a flow volume ratio of fuels supplied to the respective burners is set in accordance with a value indicated by a combustion load command, which is the temperature of an inlet of a turbine into which combustion gas from the combustor flows made dimensionless. Furthermore, this technology suppresses combustion oscillation that may occur during runback operations, which are operations for quickly reducing the load, by changing the fuel flow volume ratio determined in accordance with the combustion load command value during the runback operations.